@Nick Ashley,
Just noticed I didn't answer the second part of the question.
Juno - This was so original, I smiled the whole way through it. It was not at all what I expected (having the kid from superbad in it, I was expecting more of a 'superbad' type of movie). However, it was really funny, in a new way.
Walk Hard - I had very low expectations for this one. However it turned out to be a great movie, with a ton of good one-liners that I will quote for years to come. I didn't think John C. Riley would be strong enough to be the lead character, and I was dead wrong. I went in thinking "Why isn't the lead played by Will Ferrel" and left thinking that Will Ferrel didn't need to be in it.
21 - I'd heard of the story long before (based on true events). It was glamorized and 'hollywood-ized' very well in my opinion. After watching it, I went to wikipedia to see what was true and what wasn't. I like movies that make me do that.
As for what Step Brothers and Forgetting Sarah Marshall, they have been highly recommended to me. I actually might have just been convinced to pay the money to see Step Brothers in the theater this week. I haven't been to a theater since Superbad was released.